PR review for deprecating keyword, order, from factorize().

  - Change none to None in docs.
  - Change warning message to be consistent with other phrasing.
  - Add tests to catch FutureWarning when order keyword is passed to factorize.

Author: eric

pandas/tests/test_algos.py

@@ -248,6 +248,13 @@ def test_uint64_factorize(self):
         tm.assert_numpy_array_equal(labels, exp_labels)
         tm.assert_numpy_array_equal(uniques, exp_uniques)
 
+    def test_deprecate_order(self):
+        data = np.array([2**63, 1, 2**63], dtype=np.uint64)
+        with tm.assert_produces_warning(expected_warning=FutureWarning):
+            algos.factorize(data, order=True)
+        with tm.assert_produces_warning(False):
+            algos.factorize(data)
+
 
 class TestUnique(object):
 

pandas/util/_decorators.py

@@ -66,7 +66,7 @@ def deprecate_kwarg(old_arg_name, new_arg_name, mapping=None, stacklevel=2):
     old_arg_name : str
         Name of argument in function to deprecate
     new_arg_name : str | None
-        Name of preferred argument in function. Use none to raise warning that
+        Name of preferred argument in function. Use None to raise warning that
         ``old_arg_name`` keyword is deprecated.
     mapping : dict or callable
         If mapping is present, use it to translate old arguments to
@@ -111,7 +111,8 @@ def wrapper(*args, **kwargs):
 
             if new_arg_name is None and old_arg_value is not None:
                 msg = (
-                    "the '{old_name}' keyword is no longer supported"
+                    "the '{old_name}' keyword is deprecated and will be"
+                    "removed in a future version"
                     "please takes steps to stop use of '{old_name}'"
                 ).format(old_name=old_arg_name)
                 warnings.warn(msg, FutureWarning, stacklevel=stacklevel)